U.S. Pat. No. 3,539,115 discloses a pump and a ball mill wherein rotational movement is imparted to a fluid medium by a powered impeller, causing a plurality of balls to roll about spaced shoulders on a stationary ball race assembly. Fluid circulation is provided from the area of the impeller, about the balls and through apertures in the ball race assembly to the area outward of the race assembly.
The present disclosure has structural features generally common to the pump and ball mill or hydraulic mill disclosed in U.S. Pat. No. 3,539,115. It functionally complements the utilization of the hydraulic mill described in that patent in that it creates maximum grinding pressure at the minimum flow rate through the assembly and maximum grinding rate at the maximum flow rate. In the previously disclosed unit, the maximum grinding rate and pressure required a high flow rate and the centrifugal forces created by the balls about the stationary ball race assembly were in direct relationship to the flow rate. In the present fluidic mill, the centrifugal forces are inversely proportional to the flow rate. This permits attainment of grinding pressures much greater than were previously available without increasing the size of the ball race assembly, the size of the balls or other rollers, or rotational speed.